Dosing and uses of Panhematin (hemin)
Adult dosage forms and strengths
lyophilized powder for reconstitution
- ~301mg/vial
- ~7mg/mL (after reconstitution)
Acute Intermittent Porphyria
Indicated for amelioration of recurrent attacks of acute intermittent porphyria temporally related to the menstrual cycle susceptible women
Similar efficacy reported in other patients with acute intermittent porphyria, porphyria variegata, and hereditary coproporphyria
Before administering hemin, consider an appropriate period of alternate therapy (ie, 400 g glucose/day for 1-2 days); if improvement is unsatisfactory, then initiate hemin
1-4 mg/kg/day IV infused over 10-15 minutes for 3-14 days based on the clinical signs
In more severe cases this dose may be repeated no earlier than q12hr
Not to exceed 6 mg/kg/24 hr
Dosing Considerations
Confirm presence of acute porphyria by presence of clinical symptoms and a positive Watson-Schwartz or Hoesch test
May monitor declining urinary concentrations of aminolevulinic acid, uroporphyrinogen, porphobilinogen, and coproporphyrin to demonstrate hemin’s efficacy
Pediatric dosage forms and strengths
<16 years: Safety and efficacy not established
Panhematin (hemin) adverse (side) effects
Frequency not defined
Phlebitis with or without leucocytosis or pyrexia when administered through small arm veins
Postmarketing Reports
Reversible renal shutdown has occurred with excessive doses
Warnings
Black box warnings
Only be used by physicians experienced in the management of porphyrias in hospitals where the recommended clinical and laboratory diagnostic and monitoring techniques are available
Hemin therapy should be considered after an appropriate period of alternate therapy (ie, 400 g glucose/day for 1-2 days)
Contraindications
Hypersensitivity
Cautions
Made from human blood; may carry risk of infectious agents including Creutzfeldt-Jakob disease
Clinical benefit from hemin depends on prompt administration; attacks of porphyria may progress to a point where irreversible neuronal damage has occurred; hemin therapy is intended to prevent an attack from reaching the critical stage of neuronal degeneration and is not effective in repairing neuronal damage
May increase iron and serum ferritin levels
Not indicated in porphyria cutanea tarda
Reversible renal shutdown has been observed in a case where an excessive hematin dose (12.2 mg/kg) was administered in a single infusion; treatment of this case consisted of ethacrynic acid and mannitoL
Pregnancy and lactation
Pregnancy category: C
Lactation: Unknown whether distributed in breast milk
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Panhematin (hemin)
Mechanism of action
Limits rate of hepatic and/or marrow porphyria/heme biosynthesis, possibly by inhibiting the enzyme aminolevulinic acid synthetase
Also exhibited transient, mild anticoagulant effects during clinical trials
Administration
IV Preparation
Reconstitute lyophilized powder by aseptically adding 43 mL of sterile water for injection
Immediately after adding diluent, vigorously shake vial for 2-3 minutes to aid dissolution
The reconstituted solution is not transparent, any undissolved particulate matter is difficult to see when inspected visually; therefore, terminal filtration through a sterile 0.45 micron or smaller filter is recommended
Contains no preservative and undergoes rapid chemical decomposition in solution; do not reconstitute until immediately before use
After the first withdrawal from the vial, any solution remaining must be discarded
IV Administration
Infuse IV over 10-15 minutes
Administer via large arm vein or central venous catheter to avoid phlebitis
Terminal filtration advised
Storage
Unreconstituted lyophilized powder: Store at controlled room temperature of 20-25°C (68-77°F)
Reconstituted solution: Contains no preservative and undergoes rapid chemical decomposition; use immediately and do not store
